Method for producing nitric oxid.



I. L. ROBERTS.

METHOD FOR PRODUGING NITRIC OXID.

APPLICATION FILED I'll-3120,1907.

Patented Nov. 3, 1908.

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qwi/bnwwo fil -r, 6 4 a WW I ,thereof, is a socketed holder or other suit- ISAIAH L. ROBERTS,

OF NEW Yonx, N. Y.

METHOD FOR PRODUCING NITRIC OXH).

Specification of Letters Patent.

Patented Nov. 3, 1908.

Application filed February 20, 1907. Serial No. 368,377.

To all whom it may concern:

Be it known that I, ISAIAH L. RoBERTs, a cltizen of the United States, residing at New York, in the county and State of New York, have invented certain new and useful Improvements in Methods for Producing Nitric Oxid, of which the following is a specification, reference being had to the drawing accompanying and forming part of the same.

My invention relates to the production of n tric oxid gas by direct combination of the nitrogen and oxygen of the air, and has for lts object to provide a method and apparatus by which this direct combination can be effected more rapidly than has heretofore been possible and by which a greater proportion of the nitrogen and oxygen constituents of the air can be made to combine.

The invention will be more readily understood from a description of the preferred form of apparatus, and the same is shown, somewhat diagrammatically, in the annexed drawing.

Therein, Figure 1 shows the apparatus in vertical cross-section- Fig. 2 is a horizontal section taken on line II-II.

Referring now to the drawing, 1 indicates a casing or chamber, preferably of rectangular prismatic form, mounted on a base 2- and provided at one side with a hinged door or closure 3. Extending inwardly from the opposite side of the chamber is a web or fin 4:, spaced from the top and bottom or base of the chamber and carrying on its edge a half-cylinder 5. Extending inwardly from the door 3 is a similar web or fin 6, carrying a similar half-cylinder 7, the parts being so proportioned and arranged that when the door is closed the two half-cylinders will be brought together edge to edge, thus forming a Vertically extending hollow cylinder at about the center of the casing, openat top and bottom, as shown. On the base 2, immediately below the cylinder and at the axis able device 7 for holding an electrode 8, while at the top of the casing is a vertically adjustable holder 9 for another electrode, 10. The lower holder is connected by a lead 11 with one terminal of a source of current, the lead passing through an insulating bushing 12 in the wall of the apparatus. The casing itself being preferably of iron, the upper electrode may be connected with the source of current by connecting the lead 13 to the casing, as will be readily understood.

At the base of the casing is an air inlet opening 14, and at the top is a pipe 15 or other suitable means for leading off the products formed in the cylinder.

The operation of the foregoing apparatus will be readily understood. An arc having been established between the electrodes 8 and 10, the heat of the arc immediately causes a flow of air through the cylinder, the air entering the casing through the aperture 14 and leaving the apparatus through the pipe 15. As the air passes the arc the intense heat thereof causes more or less of the nitrogen and oxygen to combine, producing nitric oxid gas, (N0 or N 0,). If any water be present, more or less of the oxid will combine therewith, forming nitric acid, and the remaining nitric oxid can be subsequently combined with the proper proportion of water in any well understood way.

The apparatus just described is simple and compact, and possesses marked advantages over other apparatus with which I am familiar for the same purpose. The cylindrical passage confines the air in a small space about the arc, so that the air current is more efiectively subjected to the heat of the arc, while the outer casing or chamber acts not only as an inclosure for the other parts but also serves to confine a body of air about the cylinder, which body of air serves as a heat-insulator and retains the heat well, practically the only loss of heat being by conduction in the thin webs which carry the half-cylinders. Constructing the cylindrical passage in halves, one half carried by the door and the other by the opposite wall of the casing, is also of material advantage, inasmuch as instant access to all parts, of the apparatus for inspection, repair, replacement of electrodes, etc., may be had merely by opening the door of the casing.

While good results can be secured with the above apparatus using electrodes of ordinary carbon I have found markedly superior results can be obtained with electrodes containing chromium, or chromium and iron. With such electrodes a so-called flaming arcis produced between them, containing chromium, or chromium and iron if the latter metal is also present in the electrodes, and I find that such an arc produces a much more rapid combination of the nitrogen and oxygen, so that more of these two gases are.

combined, with correspondingly greater production of the nitric oxid. My improved,

method of producing nitric oxid therefore consists, broadly, in subjecting the nitrogen and oxygen to a flaming arc containlng chromium, or chromium and iron.

Electrodes for the purpose in hand may be made in various ways, but I prefer to make them by casting an alloy of iron and chromium, the chromium being present preferably in as large proportion as is possible and still permit the alloy to be melted and cast in good form. With electrodes thus made the arc is composed of the vapor of iron and chromium or low oxids thereof; and these being better conductors than the vapor of carbon or the carbon particles constituting the arc formed between carbon electrodes, the chromium, or chromium-iron arc can be drawn out to a greater size with the same current than can the carbon arc. The large or so-called flaming are so produced causes a larger proportion of the nitrogen and oxygen to be acted on than does the smaller carbon arc, and thus materially increases the quantity of oxid produced. Instead of electrodes composed entirely of metal or metals, I may employ, with good results, electrodes like those described in prior patents granted to me Nos. 460,595, dated October 6, 891, and 786,518, dated April 4, 1905, whic describe electrodes containing chromium or chromium and iron.

1. The method of producing nitric oxid,.

which consists in subjecting a mixture of nitrogen and oxygen to an electric are con-' taining chromium, as set forth.

2. The method of producing nitric oxid, which consists in subjecting a mixture of nitrogen and oxygen to an electric are containing chromium and iron, as set forth.

3. The method of producing nitric oxid, which consists in passing a current of oxygen and nitrogen in contact with an electric arc containing chromium, as set forth.

4. The method of producing nitric oXid, which consists in continuously supplying a mixture of nitrogen and oxygen to the lower end of a tubular passage, maintaining in said passage a flaming electric arc containing chromium, and conducting off the resulting -product from the upper end of.- the passage,

as set forth.

ISAIAH L. ROBERTS. Witnesses;

S. S. DUNHAM, ARTHUR E. MAHAN. 

